In the use of zeolites as molecular sieves and catalyst supports, a great effort has been made to improve selectively the activity of these catalysts by devising a heterocatalyst system with the zeolite acting as a catalyst and a metal deposited on or reacted (in the formation of the zeolite) therewith, thus due to its molecular sieve function further enhancing the catalytic activity of the zeolite. This invention, however, pertains to the selective activity of the heterocatalyst system wherein the metal is deposited, i.e. reacted, within the pores or the cage of the zeolite in a specific replacement by a metal complex. This invention, therefore, must be distinguished from the, in gross, modification of the zeolite systems incorporating metals in these in a random fashion or in the production of these zeolites or by subsequent exchange or ion replacement, in gross and other methods disclosed in the art.
In the art of zeolite chemistry, a number of conventions have been adopted for characterizing the molecular sieve zeolites. For purposes of the present invention, the molecular sieve zeolites will be defined by the terminology found in Experimental Methods in Catalytic Research, Volume 2, "Preparation and Examination of Practical Catalysts", Chapter 1 authored by A. P. Bolton, and entitled "Molecular Sieve Zeolites", Academic Press, Inc., (1976), and includes from Table I therein the suitable zeolites as further defined below, i.e. Type X, Y, Mordenite, L, Erionite, and Zeolite .OMEGA., but any other structure formed by other arrangements in pores, apertures, or cages is intended as long as appropriate dimensions are met, either for the metal complex or the zeolite structure.